Hyperbee.Expressions 1.0.0-develop.241024140338

Welcome to Hyperbee Expressions

Hyperbee.Expressions is a library for creating c# expression trees that extend the capabilities of standard expression trees to handle asynchronous workflows and other constructs.

Features

• Async Expressions

  • AwaitExpression: An expression that represents an await operation.
  • AsyncBlockExpression: An expression that represents an asynchronous code block.

• Using Expression

  • UsingExpression: An expression that automatically disposes IDisposable resources.

• Looping Expressions

  • WhileExpression: An expression that represents a while loop.
  • ForExpression: An expression that represents a for loop.
  • ForEachExpression: An expression that represents a foreach loop.

• Supports Fast Expression Compiler (FEC) for improved performance.

Examples

Asynchronous Expressions

The following example demonstrates how to create an asynchronous expression tree.

public class AsyncExample
{
    public async Task ExampleAsync()
    {
        // Variables to store the results
        var result1 = Expression.Variable( typeof(int), "result1" );
        var result2 = Expression.Variable( typeof(int), "result2" );

        // Define two async method calls

        var instance = Expression.Constant( this );

        var awaitExpr1 = ExpressionExtensions.Await( 
            Expression.Call( instance, nameof(FirstAsyncMethod), Type.EmptyTypes ) 
        );

        var awaitExpr2 = ExpressionExtensions.Await( 
            Expression.Call( instance, nameof(SecondAsyncMethod), Type.EmptyTypes, result1 )
        );

        // Assign the results of the await expressions to the variables
        var assignResult1 = Expression.Assign( result1, awaitExpr1 );
        var assignResult2 = Expression.Assign( result2, awaitExpr2 );

        // Create an async block that calls both methods and assigns their results
        var asyncBlock = AsyncExpression.BlockAsync(
            [result1, result2],
            assignResult1,
            assignResult2
        );

        // Compile and execute the async block
        var lambda = Expression.Lambda<Func<Task<int>>>( asyncBlock );
        var compiledLambda = lambda.Compile();
        var resultValue2 = await compiledLambda();

        Console.WriteLine( $"Second async method result: {resultValue2}" );
    }

    public static async Task<int> FirstAsyncMethod()
    {
        await Task.Delay( 1000 ); // Simulate async work
        return 42; // Example result
    }

    public static async Task<int> SecondAsyncMethod( int value )
    {
        await Task.Delay( 1000 ); // Simulate async work
        return value * 2; // Example result
    }
}

Using Expression

The following example demonstrates how to create a Using expression.

public class UsingExample
{
    private class DisposableResource : IDisposable
    {
        public bool IsDisposed { get; private set; }

        public void Dispose()
        {
            IsDisposed = true;
        }
    }

    public void UsingExpression_ShouldDisposeResource_AfterUse()
    {
        var resource = new TestDisposableResource();

        var disposableExpression = Expression.Constant( resource, typeof( TestDisposableResource ) );
        var bodyExpression = Expression.Empty(); // Actual body isn't important

        var usingExpression = ExpressionExtensions.Using( 
            disposableExpression, 
            bodyExpression 
        );

        var compiledLambda = Expression.Lambda<Action>( reducedExpression ).Compile();

        compiledLambda();

        Console.WriteLine( $"Resource was disposed {resource.IsDisposed}." );
    }
}

Credits

Special thanks to:

• Sergey Tepliakov - Dissecting the async methods in C#.
• Just The Docs for the documentation theme.

Contributing

We welcome contributions! Please see our Contributing Guide for more details.